1. Field of the Invention
The present invention relates to a sound-absorbing panel and a production method of the same.
Priority is claimed on Japanese Patent Application No. 2006-097002, filed Mar. 31, 2006, and Japanese Patent Application No. 2007-001186, filed Jan. 9, 2007, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, a sound-absorbing panel constituted from a porous plate, a sound-absorbing panel which has a constitution of combination of both the porous plate and a porous sound-absorbing material are generally known. Japanese Patent Application No. H06-348281 discloses a sound absorbing panel which is constituted by providing multiple open aperture portions on a plate member, and by pressing, adhering and integrating the open aperture portions with a metallic porous sound-absorbing material of the same shape as these open aperture portions.
Moreover, Japanese Patent No. 3024525 discloses a metallic plate on which pierced apertures are evenly and uniformly provided, and which reduces the sound reflection rate.
Furthermore, Japanese Patent No. 2993370 discloses a sound-absorbing veneer plate which is constituted by adhering a sound-absorbing base material and a veneer material, and which is constituted by forming multiple small apertures of 0.05-0.5 mm opening diameter on the veneer plate.
On the other hand, there are many cases in which sound-absorbing panels are used as materials of a wall surface of a building; therefore, not only sound-absorbing characteristics, but also aesthetic appeal or visual appeal of the sound-absorbing panel itself is required.
However, with respect to the sound-absorbing panel described in Japanese Patent Application, First Publication No. H06-348281, as shown in FIGS. 8 and 9, the size of the open aperture is approximately as large as can be recognized by the naked eye; therefore, the metallic porous sound-absorbing material filled in this open aperture is in a state which can be recognized by the naked eye. Therefore, there is a problem in which the appearance of this sound-absorbing plate is determined in accordance with the size of the open aperture and the appearance of the metallic porous sound-absorbing material, and there is a small freedom of design.
Moreover, with respect to the metallic plate disclosed in Japanese Patent No. 3024525, as shown in FIGS. 1-8, a radius of the pierced aperture is set to be 8-28 mm, gaps or intervals between the pierced apertures are set to be 20-100 mm which are comparatively large; and therefore, the pierced apertures are set to be a size which can be recognized by the naked eye. Therefore, there is a problem in which the appearance of the metallic plate is mainly determined in accordance with the radius and intervals of the pierced apertures, and there is a small freedom of design.
Moreover, the sound-absorbing veneer disclosed in Japanese Patent No. 2993370 has limitations to the material of the veneer because a pulse laser processing machine is used upon forming fine or small apertures on the veneer; therefore, there is a problem in which the freedom of designing is small.
Moreover, with respect to the sound-absorbing plate which is obtained by combining the porous plate and the porous sound-absorbing material as described in Japanese Patent Application, First Publication No. H06-348281 or Japanese Patent No. 2993370, there is a case in which fiber sound-absorbing material such as glass wool, rock wool, and the like is used as the porous sound-absorbing material, and there is a case in which a granular sound-absorbing material that is obtained by solidifying and forming granular mineral material such as pearlite, silver sand, and the like is used. There are many cases in which the percentage of void space is applied as an indicator or an index upon choosing the constitutional material of the sound-absorbing plate among them. However, inside the fiber sound-absorbing material and the granular sound-absorbing material, vacant spaces are generated in different ways; therefore, a relationship between the percentage of void space and the maximum sound-absorbing coefficient is not uniform or constant. It is not necessarily possible to obtain a sound-absorbing plate which has an excellent maximum sound-absorbing coefficient even if the percentage of void space is applied as the indicator and the porous sound-absorbing material is selected. Moreover, even in a case in which the same fiber sound-absorbing material is used, there is possibility that the sound-absorbing coefficient is different in accordance with the thickness or length of the fiber even though the percentage of void space is the same, and even in a case in which the same granular sound-absorbing material is used, there is possibility that the sound-absorbing coefficient is different in accordance with a size of inorganic powders or inorganic particles or in accordance with adhering or sticking state of a bonding agent even though the percentage of void space is the same. In other words, even if the percentage of void space is the same, there is a difference in pass or channel in which air flows in accordance with the constitutional members; therefore, a relationship between the percentage of void space and the sound-absorbing coefficient is not uniform or constant.
Therefore, there are cases in which there are differences in the maximum sound-absorbing coefficient depending on the state of the constitutional members even though the porous sound-absorbing material of the same percentage of void space is applied; therefore, there are cases in which there are differences in sound-absorbing characteristics even though the sound-absorbing plate has the same constitution.
The present invention was devised with respect to the above-described backgrounds, and has an object to provide a sound-absorbing panel and a production method of the same which have excellent freedom of design and have small differences in the maximum sound-absorbing coefficients among the products.